This invention relates to a substrate support for a thermal processing chamber.
In many semiconductor device manufacturing processes, the required high levels of device performance, yield, and process repeatability can only be achieved if the temperature of the substrate (e.g., a semiconductor wafer) is tightly monitored and controlled during processing of the substrate.
Rapid thermal processing (RTP), for example, is used for several different fabrication processes, including rapid thermal annealing (RTA), rapid thermal cleaning (RTC), rapid thermal chemical vapor deposition (RTCVD), rapid thermal oxidation (RTO), rapid thermal nitridation (RTN), and rapid thermal silicidation (RTS). The temperature in an RTP chamber may exceed 1100.degree. C. and is subject to rapid change, thereby making precise control of the substrate temperature more complicated and more difficult.
Additionally, although it is desirable to provide a substantially uniform temperature throughout the substrate during many manufacturing processes, the support on which the substrate rests can affect the manufacturing system's ability to achieve such uniformity. In susceptorless systems, for example, the substrate is usually only supported around its perimeter with an edge ring. In some situations, however, the edge ring acts as a thermal load which removes heat from the edge of the substrate, thereby making it difficult to provide a uniform temperature across the substrate and interfering with the temperature measurements.